Experimental demonstration of the reduction of the number of independent electrostrictive constants of piezoelectric ceramics

In this paper, all 2 third-order dielectric constants and all 6 electrostrictive constants of lead zirconate titanate (PZT) ceramics are measured. To measure electrostrictive constants, a new novel dynamic measuring method for the capacitance variation with step and alternating stress is developed. This new method enables us to obtain the electrostrictive constants in the state of fixed polarization without an aging effect. Thus, it has been successfully confirmed that the number of independent electrostrictive constants is reduced from 6 to 2. These results are very useful not only for the drastic simplification of the measurement of electrostrictive constants of polarized piezoelectric ceramics but also for the improvement of the precision of measurement for the constants.